Conversion of hydrocarbon oils



Feb. 8, 1938. L c. HUFF CONVERSION OF HYDROCARBON OILS Filed Jan. 19,1935 INVENTOR LYMAN HUFF A ORNEY good quality;

Patented m. 8, 193a umrsn STATES? PATENT OFFICE 2.1.1.19: Y .couvaas ronor nymwcsaaon ons Lyman 0. Huh, Chicago, Ill., assignor to Universal-ilProducts Company, Chi .poration of Delaware cago, 111;, a cors u taonJanuary 19, loss, Serial No. use

11 Claims. (01.190-48) This invention particularly refers to an improved process for the selective conversion of The present" invention isparticularly well adapted to the treatment of hydrocarbon oils ofrelatively wide boiling range such ascrude petro-,- leum, topped crudeand the like although it is also advantageous as applied to thetreatment of either low-boiling or relatively high-boiling oils.

when employed for the, treatment of oils of relativelywide boilingrange, charging stock is preierablyseparated, together with theintermediate conversion products of the process, into selectedrelatively high-boiling, intermediate and low-boiling fractions. Thehigh-boiling fractions are subjected to conversion conditions ofelevated temperature and superatmospheric pressure in a heating coil and,theresulting heated products are introduced into a coking chamber,preferably operated ata. relativelylow superatmospheric pressure,wherein their high-boiling components are reduced to coke.Vaporousprodnets are withdrawn fromthe coking zone and a anyhigh-boiling.-components, such astars and similar high coke-formingmaterials, are separatedtherefrom and returned to the coking chamberwhile the remaining vaporous products are subjected to fractionation.The intermediate fractions of the charging stock and reflux coni densateare subjected to independently controlled conversion conditions ofelevated temperature and superatmospheric pressure in .aseparate heatingcoil and communicating reaction chamher; the resulting vaporous andliquid conversion products separated, the l tter supplied to the cokingchamber. wherein ey are reduced'to coke, and the vaporous conversionproducts are supplied .to said fractionation together with theaforementioned remaining vaporous products from the coking operation.The relatively lowboiling fractions of the charging stock and'refluxcondensate are subjected to independently controlled conversionconditions of .elevated temperature and superatmospheric pressure inanother separate heating coil, preferably of the type wherein the oil isheated to the desired conversion temperature and then maintained at ornear the maximum conversion temperature attained for a predeterminedtime, and all or a regulated portion of the highly heated products fromthe last mentioned heating ,coil are introduced into the coking chamberto commingle therein with the materials undergoing coking and supplyadditional heat thereto to assist their reduction to coke. Theintermediate conversion" products of the process separated into saidselected relatively low-boiling, intermediate and highboi1ing fractionscomprise the reflux condensate formed by said fractionationof thevaporous products of the process and fractionated vapors of. the desiredend-boiling. point, are subjected to condensation to form the desiredfinal light distillate product ot'the process, preferably comprisingmotor fuel of highantiknock value.

- The accompanying diagrammatic drawing illustrates one specific form ofapparatus in which the process may be accomplished.

Referring to the drawing, heating coil i is located within a furnace 2,of any suitable form, by means of whichthe oil supplied thereto, in

the manner to be later described, is subjected to the desired conversionconditions of elevated temperature and superatmospheric pressure and theheated products are discharged from the reaction chamber I.

Chamber 5 isalso preferably. maintained at a substantialsuperatmospheric pressure and, al-

though not indicated in the drawing, is, preferably insulated tominimize the loss of heat therefrom by radiation. Conversion of theheated products from heating coil I, and particularly their vaporouscomponents, continues in the reaction chamber and, in the particularcase here -heating coil ,throug-h line 0 and valve 4 into illustrated,the. resulting vaporous and liquid con'version products are separated inthis zone.

liquid conversion products may be withdrawn from theilower portion ofchamber I through line I and valve I, eitheralone or together with aminor portion of the vaporous conversion products from this zone, andare directed through lines 8 and 8' wntrolled'by the respective valves land 8' into the respective coking chambers II and II wherein they arereduced to substantially dry coke, aswill be later-more fully de-'scribed. A

vaporous products evolved in coking chambers It and II, as well asanyvaporous conversion products supplied, assuch, tothe coking chambers, aswill be later more fully described, are

W thd awn irom chambers II and Ill through v 69 further conversion.

the respective lines II and II controlled, respectively, by valves l2and I2 and are directed through line l3 into separating chamber l4.Vaporous conversion products separately with- 5 drawn from reactionchamber 5 at any desired point in this zone may also be directed throughline l5 and valve I6 into separating chamber l4 also at any, desiredpoint.

Chamber I4 is preferably operated at a sub- 10 stantially reducedpressure relative to that employed in the reaction .chamber and thematerials supplied to this zone, as previously described, from thecoking chambers and, when desired, from the reaction chamber aresubstantially freed in this zone of any high-boiling components orentrained heavy liquids such as: tars and similar high coke-formingmaterials unsuitable for further conversion in any of the variousheating coils of the system. 'Liquid products removed from the materialssupplied to chamber I 4 are withdrawn from the lower portion of thiszone through line l1 and valve Hi to pump M9 by means of which they arereturned through line 20, valve 2|, line 6 and lines 8 and 8' controlledby the respective valves 9 and 9' to coking chambers l0 and I0,respectively,,for further treatment and reduction to coke. The resultingvapors are withdrawn from the upper portion of chamber l4 through line22 and valve 23 to fractionation in fractionator 24. The insuflicientlyconverted components of the vaporous products supplied to fractionator24 are will be presently described in more detail- Frac- 40 tionatedvapors of the desired end-boiling point are withdrawn, together withuncondensable gas produced by the process, from the upper portion offractionator 24 through line 25 and valve 26 and are subjected tocondensation and cooling in 45 condenser 21. The resulting distillateand gas passes through-line 28 and valve 29 to collection and separationin receiver 30. Uncondensable gas may be released from the receiverthrough line 3| and valve 32. Distillate may be with-- drawn fromreceiver 30 through line 33 and valve 34 to storage or to any desiredfurther treatment.

The selected high-boiling fractions of the reflux condensate formed infractionator 24, preferably comprising materials such as fuel I oil,

55 heavy gas oil and the like, are. withdrawn from the lower portion ofthis zone through line 35 and valve 36 to pump 31 by means of which theyare directed through line 38 and valve 39 to heating coil 40, whereinthey are subjected to The required heat is supplied to the oil passingthrough heating coil 40 to subject it to the desired conversionconditions of elevated temperatureand superatmospheric pressure by meansof a furnace 4| of any suitable 65 form and the heated products aredischarged from heating coil 40 through line 42 and valve 43 and areintroduced into coking chambers Ill and I0 through the respective lines44 and {54' controlled respectively by valves 45 and 45.

The selected intermediate fractions of the reflux condensate formed infractionator 24, [preferably comprising materials such as gas oil andthe like may be withdrawn from a suitable intermediate point in thiszone, such as, for exam- 7 ple, through line 46 and valve 47, by means03 which they are supplied to pump 48. The oil thus supplied to pump 48is directed therefrom through line 49 and valve 50 to conversion inheating coil I, in the manner previously described.

The selectedlow-boiling fractions of the reflux condensate formed infractionator 24 preferably comprising such materials as pressuredistillate .bottoms, kerosene or kerosene distillate and the for furtherconversion.

Heating coil 56 is located within a furnace 51 of any suitable form andpreferably comprises a heating coil of the type wherein the oil suppliedthereto is heated to or near the maximum desired conversion temperatureand then maintained at a substantially constant temperature approach ingthe maximum attained for a predetermined time. The furnace illustratedis of the double end-fired" type which permits independent control ofthe heating conditions about different portions of the heating coilwhereby a heating curve of the desired type may be readily obtained. The

stream of highly heated products is discharged from heating coil 56through line 58 and valve 59 and may be supplied, in part, through line62 and valve 63 into separating chamber l4. However, a regulatedportion, at least, of the heated products from heating coil 56 ispreferably introduced into coking chambers l0 and I0 through lines and60'respectively, controlled by the respective valves 6| and 6| whereinthe highly.

heated products are directly commingled with the materials undergoingcoking and supply additional heat thereto for the purpose of assistingtheir reduction to coke.

Coking chambers l0 and ID are similar zones, preferably operated at asubstantially reduced pressure relative to that employed in reactionchamber 5, wherein reduction of the residual liquid conversion productsof the process to coke is accomplished. It will be understood, ofcourse, that only one coking chamber or any desired number of such zonesmay be employed, although two are illustrated in the drawing. Coke maybe allowed to accumulate within the coking chamber until it issubstantially filled following which it may be cooled, cleaned andprepared for further operation in any well known manner, notillustrated. When a plurality of coking chambers is employed thechambers preferably 'are alternately operated, cleaned and prepared itsoperation is completed and after it has been I isolated from the rest ofthe system, in order to hasten cooling and facilitate the-removal ofcoke therefrom.

Hydrocarbon oil charging stock for the system is supplied, in the casehere illustrated, through line 64 and valve 65 to pump 66 by means ofwhich it is fed through line 61.

When the charging stock comprises an oil of relatively wide boilingrange which, however, does arcane not contain any appreciable quantityof highboiling materials unsuitable for conversion in heating coil ll itis preferably directed, all or in part, from line 01 through line It andvalve .into fractionator 20, wherein it is sublected toportion or all ofthe charging stock to fractionator it regardless of its characteristicsso long i as it does not contain any appreciable quantity of 'materialsof a high coke-forming nature unsuitable for conversion in heating coil40 and does not. contain any appreciable quantity of motor fuel ormotorfuel fractions of inferior quality which will contaminate theoverhead vaporous terials unsuitable for conversion in heating coil 40it ispreferably. directed from line 01 through lines II and II, valvel2, line I0 and valve It into vaporieing chamber ll, wherein itshigh-boiling components remaining unvaporiaed in this sons 1 maycommingle with the heavy liquid conversion products supplied from thisnone, as previously described, to "the coking lone, while any lowerboiling vaporous components of the charging may be supplied to chamberit, in the manner described, regardless of its characteristics, servingas a cooling and refluxing medium in this zone and preferably whenemployed for this purpose it is introduced, as indicated in the drawing,into the upper portion of the chamber and allowed to 3 of the refluxcondensate from line ll through line flow downward therethrough.

the charging stock not supplied to the fractionator, as a.cooling andrefluxing medium in chamber II. This may be accomplished by divertingregulated quantities of the high-boiling fractions ll, valve 8i and linell, preferably into the upper portion of chamber ll.

,- It will be understood that the invention is-not limited to thespecific form of apparatus illustrated norto the' speciflc processdescribed.

The preferred range of operating conditions which may be employed toaccomplish the ob- Jectsof the present invention, in an apparatus of thecharacter illustrated and above described.

may be approximately as.fol1ows: The light oil heating coil to whichlow-boiling fractions of the reflux condensate are suplied forconversion or I reforming, either alone ortogether with charging stockor low-boilingfractions thereof, preferably employs. an outletconversion temperature of the order of 950 to 1.100" F., preferably witha superatmospheric pressure measured at this point 'in the system whichmay range, for example, from 800 to 1,000 pounds, or thereabouts, persquare inch. As previously indicated, the ilnal stages of this heatingcoil preferably comprise the soaking" section wherein the oil previouslyheated to or near the maximum desired conversion temperature ismaintained at a substantially constant temperature, near the maximum,for a predetermined time. The heavy oil heating coll whereinhigh-boiling fractions of the reflux condensate are subjected toconversion, either alone or together with high-boiling charging stock orhighboiling fractions of the charging stock, may employ an outletconversion temperature ranging, for example, from 800 to 950 l".,preferably with a superatmospheric pressure measured at the outlet fromthe heating coil of from 100 to 500 pounds, or more, per square inch.The heating coil to which intermediate fractions of the refluxcondensate are supplied for conversion, either alone or together withcharging stock or charg ing stock fractions of corresp ndingcharacteristics, may employ an outlet conversion temperature of from 900to-1,000' It, preferably with a superatmospheric pressure at this pointin the system of the order of 200 to 800 pounds, or

thereabouts, per square inch. The reaction chamber succeeding the lastmentioned heating coil preferably employs a substantial superatmosphericpressure, which may be substantially the,

same or somewhat lower than that employed in the preceding heating coil.The coking chambers are preferably operated at a substantially reducedpressure relative to that employed in the reaction chamber ranging, forexample, from, 100 pounds, or thereabouts, per square inch, down tosubstantially atmospheric pressure. The separating chamber to whichvaporous products from the coking chamber are supplied preferablyemploy's substantially the same or somewhat lower pressure than thatutilized in the coking zone. The

'fractionating, condensing and collecting portions of the system mayemploy pressures substantially the same or somewhat lower thanthatemployed in the separating chamber.

As a speciflc example of one of the many possible operations of theprocess of the present invention as it may be accomplished in anapparatus such as illustrated and above described, the charging stock isan 18, A. P. I. gravity Mid-Continent fuel oil which is supplied, inpart, to the fractionatcr and, in part, to the separating chamberpreceding the fractionator. High-boiling fractions of the charging stockand of the reflux condensate formed in the fractionator are subiected inthe heating coil'to which they are supplied to an outlet temperature ofapproximately 900' l". at a superatmospheric pressure of about 200pounds per square inch and the heated products are introduced intoalternately operated coking chambersmaintained at a superatmosphericpressure of about 50 pounds per square inch. Intermediate fractions ofthe charging stock and reflux condensate are subjected in a separateheating coil to an outlet conversion temperature of approximately 9501",, at a superatmospheric pressure of about 400 pounds per square inch.This pressure is substantially equalized in the succeeding reactionchamber wherein vaporous and liquid conversion products are separated,the latter being supplied direct to the coking chambers while thevaporous products are supplied, together with yaporous products from thecoking chamber, to the separating chamber which ,is maintained at asuperatmospheric pressure of approximately 40 pounds per square inch.Heavy liquid products recovered in the separating chamberare alsoreturned to the coking chambers and v the vaporous products from theseparating chamber are subjected to fractionation for the formation 'ofsaid reflux condensate. The low-boiling fractions of the refluxcondensate having a boiling range of approximately 350 to 550 F. areheated in a separate heating coil to a conversion tempera- 800 poundsper square inch. The stream of highly heated products from this zone areintroduced into the coking zone and directly commingled therein with thematerials undergoing coking. This operation may produce, per barrel ofcharging stock, approximately 60 percent of 400 F. endpoint motor fuelhaving an octane number of approximately 70 by the motor method andapproximately 100 pounds of low volatile cokeof uniformly good qualityand structural strength, the remainder being chargeable, principally, touncondensable gas.

I claim as my invention:

1. In a process for the conversion of hydrocarbon oils wherein an oil.is subjected to conversion conditions of elevated temperature andsuperatmospheric pressure in a heating coil, the heated productsintroduced into an enlarged reaction chamber, also maintainedatsuperatmospheric.

pressure, wherein particularly their vaporous components are subjectedto appreciable continued conversion and wherein separation of vaporousand liquid conversion products is accomplished, the vaporous and liquidconversion products separately withdrawn from the reaction chamber, the

' heavy reflux condensate from the vaporous products of the processundergoing said fractionation, returning the light reflux condensate tothe heating coil for further conversion, subjecting the heavy refluxcondensate to independently controlled conversion conditions of elevatedtemperature and superatmospheric pressure in a separate heating coil,introducing the heated products from said separate heating coil into acoking chamber, withdrawing'liquid conversion. products from thereaction chamber and introducing the same into said coking chamber,supplying vapors from. the coking chamber to a separating chamberwherein undesirable high-boiling components, including any entrainedhigh coke-forming liquids, are removed therefrom, returning the liquidproducts from said separating chamber to the coking chamcarbon oilswherein an oil is subjected to conversion conditions of elevatedtemperature and superatmospheric pressure in a heating coil, the

heated products introduced into an enlarged reaction chamber, alsomaintained at superatmospheric pressure, wherein particularly theirvaporous components are subjected to appreciable continued conversionand wherein separation of vaporous and liquid conversion products isaccomplished, the vaporous conversion products subjectedto-fractionation whereby their insufilciently converted components arecondensed as reflux condensate, fractionated vapors of the desiredend-boiling point subjected to condensation and the resulting distillatecollected, the improvement which comprises separating the refluxcondensate formed by said fractionation of the vaporous products of theprocess into selected relatively low-boiling, intermediate and highboiling fractions, returning intermediate fractions of said refluxcondensate to the heating coil for further conversion, subjectinghigh-boiling fractions of the reflux condensate to independentlycontrolled conversion conditions of elevatedtemperature andsuperatmospheric pressure in a separate heating coil, introducing theresulting heated products into a coking chamber, withdrawing liquidconversion products from the reaction chamber and introducing the sameinto the coking chamber, supplying vaporous products from the cokingchamber to a separating chamber wherein undesirable high-boilingcomponents, including entrained high coke-forming liquids and the likeare removed therefrom, returning said undesirable high-boiling materialsto-the coking chamber, subjecting selected low-boiling fractions of saidreflux condensate to independently controlled conversion conditions ofelevated temperature and superatmospheric pressure in another separateheating coil, introducing regulated portions of the highly heatedproducts from the last mentioned heating coil into the-coking chamber,supplying the remainder of said highly heated products from the lastmentioned heating coil to said separating chamber and subjectingvaporous products remaining uncondensed in said separating chamber tosaid fractionation.

4. A process of the character defined in claim 3 wherein charging stockfor the process, comprising hydrocarbon oil of relatively wide boilingrange, is separated into selected fractions and wherein fractions of thecharging stock corresponding to said selected fractions of the refluxcondensate are subjected to conversion therewith.

5. A process of the character defined in claim 3 wherein hydrocarbon oilcharging stock for the process is supplied, at least in part, to thefractionating stage of the system.

6. A process of the character defined in claim 3wherein hydrocarbon oilcharging stock for the process is supplied, at least in part, to saidseparating chamber.

"7. The process as defined in claim 3 further characterized in thathydrocarbon oil charging stock for the process is supplied in separateportions to the fractionating stage of the system and to said separatingchamber.

8. A hydrocarbon oil conversion process which comprises fractionatinghydrocarbon vapors,

formed as hereinafter set forth, to separate relatively heavy,intermediate and light reflux condensates therefrom, heating the heavyreflux condensate to cracking temperature under pressure in a heatingcoil and then discharging the same into a coking zone, subjecting theintermediate reflux condensate to independently controlled crackingconditions of temperature and pressure in a secondheating coil andseparating resultant vapors from unvaporized oil in an enlarged reactionzone, separately removing vapors and unvaporized oil from the reactionzone and introducing the latter to the coking zone, distilling theheated heavy reflux condensate and the unvaporized oil to coke in thecoking zone, subjecting the light reflux condensate in a third heatingcoil to more drastic cracking, than the,

heavy and intermediate reflux condensates, discharging heated productsfrom said third coil into the coking zone to assist the coking operationtherein, supplying vapors from the coking zone and from the reactionzone to the fractionating step, and flnally condensing the fractionatedvapors. a

9. The process as defined in claim 8 further characterized in that heavycoke-forming components are separated from the vapors from the cokingzone prior to the fractionation of these vapors and such separated heavycomponents returned to the coking zone. l

10. A hydrocarbon oil conversion process which comprises i'ractionatinghydrocarbon vapors, formed as hereinafter set forth, to separaterelatively heavy, intermediate and light reflux condensates therefrom,heating the heavy reflux condensate to crackin'gtemperature underpressure in a heating coil and then discharging the same into a cokingzone, subjecting thedntermediate reflux condensate to independentlycontrolled cracking conditions of temperature and pressure in a secondheating coil and separating resultant vapors from unvaporized oil in anenlarged reaction zone, separately removing vapors and unvaporized oilfrom the reaction zone and introducing the latter to the coking zone,distilling the heated heavy reflux condensate and the unvaporized oil tocoke in the coking zone, subjecting the light reflux condensate in athird heating coil to more drastic cracking than the heavy andintermediate reflux condensates, discharging heated products from saidthird coil into the coking zone to assist the coking operation therein,introducing the vapors from the coking and reaction zones into acontacting zone and therein contacting the same with fresh charging oilfor the process, thereby separating heavy components of the vapors andvaporizing the charging oil at least in part, supplying the commingledvapors from the contacting zone to the fr'actionating step, and flnally,condensing the fractionated vapors.

11. The process as deflned in claim 10 further characterized in thatliquid products separated in the contacting zone are introduced to thecoking zone.

LYMAN C. HUM".

